Autunite.
This autunite was donated by the mine owner who dug it up: It's a lovely specimen, photographed here under ultraviolet light. The main picture for this sample actually shows the back side of the sample, which has some very nice large crystals. The front side is completely covered with more autunite crystals: Click the turntable icon on the right to get an image you can rotate around and see from all sides.
You can get samples of this an other radioactive minerals direct from the mine.Source:eBay seller boomologistContributor:Theodore GrayAcquired:25 June, 2005Price: DonatedSize: 1.5"Composition:Ca(UO2)2(PO4)2.10H2O